Electric heating apparatus



(No Model.) 2 Sheets-Sheet 1.

R. A. L. SNYDER & A. F. TINNERHOLM; ELECTRIC HEATING APPARATUS No.566,545. Patented Aug. 25, 189.6.

Attorney- (No Model.) 2 Sheets-Sheet 2.

R. A. L. SNYDER 8a A. F. TINNERHOLM.

ELECTRIC HEATING APPARATUS.

ym ma .IIIIIIIII Patented Aug. 25, 1896.

Witnesses:

e .www

Attorney-f UNITED STATES l PATENT OFFICE.

RICHARD A. L. SNYDER AND AUGUST F. TINNERHOLM, CF PITTSBURG,PENNSYLVANIA, ASSIGNCRS TO THE AMERICAN ELECTRICAL HEATER COMPANY, OFDETROIT, MICHIGAN.

ELECTRIC HEATING APPARATUS.

SPECIFICATION forming part of Letters Patent No. 566,545, dated August25, 1896. Application llledil'uly 23, 1895. Serial No. 556.908. (Nomodel.)

To aZZ whom it may concern,.-

Be it known that we, RICHARD A. L. SNY- Dnn and AUGUST F. TINNERHOLM,citizens of the United States, residing at Pittsburg, in the county ofAllegheny and State of Pennsylvania, have invented certain new anduseful Improvements in Electric Heating Apparatus; and We do herebydeclare the following to be a full, clear, and exact description of theinvention, such as Will enable 0thers skilled in the art to whichitappertains to make and use the same. v

Our invention relates to vimprovements in electric heating apparatus,and more especially to that class of electric heating apparatus in whichan induced current of electricity is employed.

In electric heating apparatus of this class heretofore generallyemployed great difficulty has been encountered by reason of the primarycoil becoming too hot and frequently burning out. The prime objects ofour invention are to obviate this serious difficulty, to concentrate theheat at the point Where required, and at the same time to produce asimple and durable apparatus. These objects We attain by theconstruction and arrangement of parts, as more fully hereinafterdescribed and particularly claimed.

Our invention is illustrated in the accompanying drawings, in which Wehave shown our invention as applied to various forms of heating devices.

Figure l isa plan view of our invention as applied to heating a flatplate; Fig. 2, anend view of same Fig. 3, an end View of a radiatorembodying our invention; Fig. 4, a plan view showing arms of radiator;Fig. 5, a sectional view of a fiat-iron Fig. 6, aplan view of same, andFig. 7 a cross-section of a soldering-iron.

Like letters of reference indicate like parts throughout the severalfigures.

Referring to the drawings, a indicates a soft-iron core, either solid ormade up of Wires.

s is made of copper, iron, or other suitable material', and constitutesthe short-circuited secondary surrounding the iron core a.

Z are metal lugs attached to the secondary in such a manner as tocollect the heat from the secondary, store it up when not beingutilized, and give it out When and where required Without materiallylowering the resistance of the secondary.

p is the primary coil, placed either on the outside of the secondary sor betweenV it or partly over it, as is shown bythe drawings. By the useof this construction we are enabled to prevent the primary from burningout, part of its surface being exposed for radiation. As a furthersafeguard, we Wind the primary coil With asbestos-covered wire.

Suitable insulating material is employed in the construction of thevarious styles of apparatus to which our invention is adapted.

To enable our invention to be better understood, We have thought it bestto show it applied to various forms of heating apparatus, and we willrefer to these forms in detail.

In Figs. l and 2 we have shown a construction adapted for heating a flatplate@ for use in connection with various cooking utensils, &c. Here Wehave shown the primary coil p placed between the secondary, by whichconstruction it is impossible for the primary to become too hot and burnout. The plate t' and the heavy parts s constitute the short-circuitedsecondary. vPlatet'is made of iron or other suitable material andprovided with lugs Z. The resistance of the plate 1I should berelatively high compared With the other parts of the secondary, and atthe same time have some capacity for storing up heat when the current ison and the heater not in use; The form of the secondary s is made of oneturn, and is of as little resistance as possible Without being toobulky. It has been proven that a fullloaded hedgehog transformer is moreefficient than a full-loaded transformer with a closed magnetic circuit.For this reason We simply insert an iron core a, as shown.

Figs. 3 and 4 show a radiator for heating rooms. Instead of the plate tof Figs. l and 2 we employ long strips of iron e in the secondarycircuit, as shown in Figs. 3 and 4. These strips are attached to aspider-casting at the top, so as to hold the .strips apart and permittheir heat to radiate. In other respects the radiator is like the heatershown in Figs. 1 and 2.

In Figs. 5 and G we show our invention applied to a iiat-iron, in whicha is the iron core; i, the plate to be heated, and which also forms partof the secondary circuit. p is the primary coil placed between thesecondary s, but with part of its surface exposed. The lugs Z serve tocollect the heat when the current is on and the flat-iron not in use,but when the flat-iron is in use the heat is given up very rapidly bythe plate fi, and as the temperature of the plate falls below that ofthe lugs the heat commences to flow through the necks of the lugs backinto the plate, thus helping it keep up the heat of the plate '11, or,in other words, the lugs act as a heat-reservoir. Just over the top ofthe heating apparatus is placed some good non-heat-conducting substanceo, as asbestos, for the purpose of turning all the heat possible downthrough the face of the flat-iron.

Fig. 7 shows a longitudinal cross-section of a soldering-iron. a is theiron core held in the secondary S by soft-iron screws w, whichconstitute part of the magnetic circuit. On the forward end of thesecondary s is an enlarged projection or lug Z, made of copper or othersuitable material, which also serves as the tip for the soldering-iron.It may be made integral with the secondary or may be a separate pieceand suitably attached thereto. The cross-section of the secondary s isincreased in area as it approaches the part or projection Zfor thepurpose of more readily delivering its heat to said lug or tip l.Practically nearly all the heat will be developed in the secondary s,which is tapered to a very small section toward the end farthest fromthe tp,so as to offer as little surface forheat radiation in thatdirection as possible. p is the primary coil, wound on the outside ofthe secondary and insulated therefrom by a thin layer of mica or othersuitable insulation, by which arrangement the primary will be keptcomparatively cool, its inner surface only being exposed to a source ofheat. Over the primary and around the ends is placed some goodnon-heat-conducting substance m, and over this is placed a thin metalshell for mechanical protection. The shellt is split down one side, sothat it will not form a second short-circuited conductor that wouldradiate its heat to the air. w is a washer made of mica or some othernon-heating material, placed between the iron and its handle to preventthe heat from going in the direction of the handle.

I-Iaving thus fully described our invention, what we claim is- 1. In anelectric heating apparatus, an open magnetic core, a short-circuitedsecondary entirely surrounding the said core, a primary coil wound onthe outside of the said shortcircuited secondary, substantially asdescribed.

2. In an electric heating apparatus, a shortcircuited divided secondaryformed of the heavy parts of low resistance and one or more plates orstrips of comparatively high resistance provided with heat-storing lugs,a softiron core running through the heavy parts of said secondarycircuit, a primary coil wound on the outside of the core and placedbetween the heavy parts of the said secondary, butinsulated therefrom,substantially as described.

3. In an electric heating apparatus, a conductor, consisting of a plateor strips, provided with lugs or projections so attached as to greatlyincrease the heat capacity of the conductor without very much increasingthe conductivity, thereby allowing the heat to be stored up in said lugsor projections and given out as needed, substantially as described.

4E. In an electric heating apparatus, a shortcireuited secondaryprovided with a projection, the cross-section of said secondaryincreasing in area as it approaches the projection, an iron coreembedded in said secondary, iron screws passing through the saidprojection to hold the core in place, a primary coil wound on andsurrounding the secondary, but insulated therefrom, substantially asdescribed.

5. In an electric heating apparatus, a shortcircuited secondary, thecross-section of said secondaryincreasing in area toward the point to beheated, an iron core embedded in said secondary, a primary coil, saidprimary coil wound on and surrounding the secondary, but insulatedtherefrom, substantially as described.

In testimony whereof we affix our signatures in presence of twowitnesses.

RICHARD A. L. SNYDER. AUGUST F. TINNERHGLM. Witnesses:

JOHN M. Pnnscorr, Jr., W. G. DooLrr'rLE.

IOO

